Read microcode version using win32 registry

find_microcode_in_registry.cpp

#define WIN32_LEAN_AND_MEAN
#include <windows.h>
#include <stdint.h>

#pragma comment(lib, "Advapi32.lib")

bool tryToFindMicrocodeVersionInRegistry(uint32_t* pOutMicrocodeVersion)
{
    bool success = false;
    HKEY pProcessorRegistryKey = nullptr;
    DWORD bufferLength = MAX_PATH;

    const char* pEntryName = "HARDWARE\\DESCRIPTION\\System\\CentralProcessor\\0";
    if(ERROR_SUCCESS != RegOpenKeyA(HKEY_LOCAL_MACHINE, pEntryName, &pProcessorRegistryKey))
    {
        goto cleanup_and_exit;
    }

    uint64_t updateRevision = 0u;
    DWORD entryLengthInBytes = sizeof(updateRevision);
    if(ERROR_SUCCESS != RegGetValueA(pProcessorRegistryKey, nullptr, "Update Revision", RRF_RT_REG_BINARY, nullptr, (PVOID)&updateRevision, &entryLengthInBytes))
    {
        goto cleanup_and_exit;
    }

    *pOutMicrocodeVersion = (updateRevision >> 32u);
    success = true;

cleanup_and_exit:
    if(pProcessorRegistryKey != nullptr)
    {
        RegCloseKey(pProcessorRegistryKey);
    }
    return success;
}